Than if you want to add it to the launcher just execute it (navigate to /usr/share/applications/ and double click eclipse) and right click on the icon in the laucher and select "Keep In Laucher"
The application will now also be displayed when you search for applications in the application lens.

Launchers is just *.desktop files. You can find most of them in /usr/share/applications folder. Just Drag & Drop the *.desktop files into your unity launch bar and that's it. Or more easly, search the app with the dashboard (in serach mode with <Alt><F2> command or with the 'Application Lens' (<Super><A>) and drag and drop the shortcut from the dash to the launcher bar.

But maybe the app is a script that you created or something like this, not referenced in Ubuntu. In this case you can create your own launcher as Leron said (you can change the icon too ;) )